Typescript (photocopy). Thesis submitted under title: Biochemical aspects of early pregnancy in the pig; but doctorate conferred to title: Biochemical aspects of early pregnancy in the sow Includes bibliographical references (leaves 178-205) and list of personal publications related to pig physiology (leaves vi-vii) Examines aspects of early pregnancy in pigs, aimed to identify determinants of the high level of embryonic mortality which occurs prior to implantation

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Typescript (photocopy). / Thesis submitted under title: Biochemical aspects of early pregnancy in the pig; but doctorate conferred to title: Biochemical aspects of early pregnancy in the sow / Includes bibliographical references (leaves 178-205) and list of personal publications related to pig physiology (leaves vi-vii) / Roseworthy Library copy has original title. / xi, 205 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines aspects of early pregnancy in pigs, aimed to identify determinants of the high level of embryonic mortality which occurs prior to implantation / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology,1985

The effect of a low-Cu diet supplied to gilts during pregnancy and early lactation on dams and their offspring was obtained in seven pairs of first littermate gilts. They were housed in stainless steel metabolism cages in a controlled environment and fed semi-purified diets containing either 2.13 or 12.25 ppm Cu from 30 days of gestation through two weeks of lactation. Feed intake was restricted to 2 kg/day during pregnancy and 4 kg/day in the first two weeks of lactation. Reproductive performance of gilts was measured. Balance studies were conducted at 30, 60 and 100 days of gestation. Mineral levels in the plasma of gilts and piglets, and in colostrum and milk were determined. The low-Cu diet did not affect (p $>$ 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs 5.71h, p 0.05). Low-Cu gilts had lower plasma Cu in early- and mid-gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p 0.05). Colostrum was richer in Cu and Zn than milk (p 0.05). Higher dry matter digestibility was observed in low-Cu gilts during early gestation (p 0.05). Compared to control gilts, the low-Cu gilts tended to have higher Cu and Zn retention which was achieved by reduction of fecal Cu and Zn excretion. Utilization of minerals appeared to increase as pregnancy progressed.

Three experiments were conducted on sows. In experiment I, Landrace gilts were fed ad libitum, from 10 weeks of age to puberty, diets containing either 2800 (LE), 3400 (ME) and 3900 (HE) Kcal DE/kg. Age at puberty was delayed in gilts fed LE and ME. Backfat thickness was significantly reduced in LE and ME groups. Puberty onset was more determined by age and backfat thickness than by weight. In experiment II, all gilts that had shown normal heat within 240 days of age, were inseminated on the second estrus and given the same diet as received during their growing period. Feed was restricted to 2.0 kg per day during gestation and was provided ad libitum in lactation. Gilts in LE and ME gained less weight and backfat during gestation than gilts in HE group. Gilts gaining more weight and backfat during gestation, with a resulting higher body weight and backfat thickness at parturition, lost more in lactation. Incidence of anoestrus after weaning was higher in the LE and HE groups. In experiment III, multiparous Landrace-Yorkshire sows from two herds were used. An extended weaning to remating interval and reduced number of piglets weaned was observed in first and second parity sows. Lower reproductive performance in one herd was related to an excessive loss of backfat in lactation and a low backfat level at weaning.